Commit 185914fd authored by Alessandro Ghedini's avatar Alessandro Ghedini Committed by Kamil Dudka
Browse files

nss: add support for TLS False Start

parent 4dcd25e1

lib/vtls/nss.c

+78 −0
Original line number Diff line number Diff line
@@ -728,6 +728,64 @@ static void HandshakeCallback(PRFileDesc *sock, void *arg) 
  }

}



static SECStatus CanFalseStartCallback(PRFileDesc *sock, void *client_data,

                                       PRBool *canFalseStart)

{

  struct connectdata *conn = client_data;

  struct SessionHandle *data = conn->data;



  SSLChannelInfo channelInfo;

  SSLCipherSuiteInfo cipherInfo;



  SECStatus rv;

  PRBool negotiatedExtension;



  *canFalseStart = PR_FALSE;



  if(SSL_GetChannelInfo(sock, &channelInfo, sizeof(channelInfo)) != SECSuccess)

    return SECFailure;



  if(SSL_GetCipherSuiteInfo(channelInfo.cipherSuite, &cipherInfo,

                            sizeof(cipherInfo)) != SECSuccess)

    return SECFailure;



  /* Prevent version downgrade attacks from TLS 1.2, and avoid False Start for

   * TLS 1.3 and later. See https://bugzilla.mozilla.org/show_bug.cgi?id=861310

   */

  if(channelInfo.protocolVersion != SSL_LIBRARY_VERSION_TLS_1_2)

    goto end;



  /* Only allow ECDHE key exchange algorithm.

   * See https://bugzilla.mozilla.org/show_bug.cgi?id=952863 */

  if(cipherInfo.keaType != ssl_kea_ecdh)

    goto end;



  /* Prevent downgrade attacks on the symmetric cipher. We do not allow CBC

   * mode due to BEAST, POODLE, and other attacks on the MAC-then-Encrypt

   * design. See https://bugzilla.mozilla.org/show_bug.cgi?id=1109766 */

  if(cipherInfo.symCipher != ssl_calg_aes_gcm)

    goto end;



  /* Enforce ALPN or NPN to do False Start, as an indicator of server

   * compatibility. */

  rv = SSL_HandshakeNegotiatedExtension(sock, ssl_app_layer_protocol_xtn,

                                        &negotiatedExtension);

  if(rv != SECSuccess || !negotiatedExtension) {

    rv = SSL_HandshakeNegotiatedExtension(sock, ssl_next_proto_nego_xtn,

                                          &negotiatedExtension);

  }



  if(rv != SECSuccess || !negotiatedExtension)

    goto end;



  *canFalseStart = PR_TRUE;



  infof(data, "Trying TLS False Start\n");



end:

  return SECSuccess;

}



static void display_cert_info(struct SessionHandle *data,

                              CERTCertificate *cert)

{
@@ -1652,6 +1710,18 @@ static CURLcode nss_setup_connect(struct connectdata *conn, int sockindex) 
    goto error;

#endif



#ifdef SSL_ENABLE_FALSE_START

  if(data->set.ssl.falsestart) {

    if(SSL_OptionSet(connssl->handle, SSL_ENABLE_FALSE_START, PR_TRUE)

        != SECSuccess)

      goto error;



    if(SSL_SetCanFalseStartCallback(connssl->handle, CanFalseStartCallback,

        conn) != SECSuccess)

      goto error;

  }

#endif



#if defined(SSL_ENABLE_NPN) || defined(SSL_ENABLE_ALPN)

  if(data->set.ssl_enable_npn || data->set.ssl_enable_alpn) {

    int cur = 0;
@@ -1929,4 +1999,12 @@ bool Curl_nss_cert_status_request(void) 
#endif

}



bool Curl_nss_false_start(void) {

#ifdef SSL_ENABLE_FALSE_START

  return TRUE;

#else

  return FALSE;

#endif

}



#endif /* USE_NSS */

lib/vtls/nssg.h

+3 −0
Original line number Diff line number Diff line
@@ -58,6 +58,8 @@ void Curl_nss_md5sum(unsigned char *tmp, /* input */ 


bool Curl_nss_cert_status_request(void);



bool Curl_nss_false_start(void);



/* Set the API backend definition to NSS */

#define CURL_SSL_BACKEND CURLSSLBACKEND_NSS
@@ -88,6 +90,7 @@ bool Curl_nss_cert_status_request(void); 
#define curlssl_random(x,y,z) Curl_nss_random(x,y,z)

#define curlssl_md5sum(a,b,c,d) Curl_nss_md5sum(a,b,c,d)

#define curlssl_cert_status_request() Curl_nss_cert_status_request()

#define curlssl_false_start() Curl_nss_false_start()



#endif /* USE_NSS */

#endif /* HEADER_CURL_NSSG_H */